We are very pleased to announce the availability of the phpBB3 RC1 package. This is the first release candidate which is meant to become the Gold release if no more bugs or problems arise. Of course there may be more than one release candidate.
phpBB users have a reason to be excited, although I am unsure at this point what all the new features are. Even though this is a release candidate, the RC1 is officially supported, which I assume means the release is very stable. If you like to live on the edge, you might want to give the latest version a go.
Source: Official phpBB Site